Enhancement of Heat-Affected Zone Toughness of a Low Carbon Steel by TiN Particle

• Published in: Metallurgical and materials transactions. B, Process metallurgy and materials processing science Vol. 47; no. 4; pp. 2148 - 2156
• Main Authors: Zhang, Yu, Li, Xiaobao, Ma, Han
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.08.2016; Springer Nature B.V
• Subjects: Austenite; Carbon steel; Characterization and Evaluation of Materials; Chemistry and Materials Science; Ferrite; Formations; Heat; Heat affected zone; Low carbon steels; Materials Science; Metallic Materials; Nanotechnology; Nitrogen; Process metallurgy; Structural Materials; Surfaces and Interfaces; Thin Films; Titanium nitride; Toughness; Acicular Ferrite; Ferrite; Bainite; Impact Toughness; Austenite
• ISSN: 1073-5615; 1543-1916
• DOI: 10.1007/s11663-015-0534-4

Enhancement of heat-affected zone toughness of a weight percentage of 0.014 pct Ti-bearing low carbon steel by TiN particle was investigated. An increase in nitrogen weight percentage from 0.0031 to 0.0083 pct results in increasing of number density of TiN precipitates from 4 × 10 3 to 3 × 10 5 /mm 2 , and reduces prior austenite grain size from 850 to 350  μ m with a soaking of 1673 K (1400 °C) for 2000 seconds. Effective refinement of austenite grain prohibits formation of ferrite side plate and/or upper bainite, and densely distributed TiN particles promote intra-granular ferrite formation, which is accompanied by an increase of 40 K to 60 K (40 °C to 60 °C) in austenite decomposition temperature during continuous cooling process. The changes in transformed products improved impact toughness of heat-affected zone efficiently, ex., increase absorbed energy of less than 42 J to more than 320 J with a simulated t 8/5 of 550 seconds.